Background: The Bernese periacetabular osteotomy (PAO) is a complex surgical procedure with a substantial learning curve. Although larger hospital and surgeon procedure volumes have recently been associated with a lower risk of complications, in geographically isolated regions, some complex operations such as PAO will inevitably be performed in low volume. A continuous structured program of distant mentoring may offer benefits when low numbers of PAOs are undertaken, but this has not been tested. We sought to examine a structured, distant-mentorship program of a low-volume surgeon in a geographically remote setting.
Questions/purposes: The purposes of this study were (1) to identify the clinical results of PAO performed in a remote-mentorship program, as determined by patient-reported outcome measures and complications of the surgery; (2) to determine radiographic results, specifically postoperative angular corrections, hip congruity, and progression of osteoarthritis; and (3) to determine worst-case analysis of PAO survivorship, defined as nonconversion to THA, in a regionally isolated cohort of patients with a high rate of followup.
Methods: Between August 1992 and August 2016, 85 PAOs were undertaken in 72 patients under a structured, distant-mentorship program. The patients were followed for a median of 5 years (range, 2-25 years). There were 18 males (21 hips) and 54 females (64 hips). The median age of the patients at the time of surgery was 26 years (range, 14-45 years). One patient was lost to followup (two PAOs) and one patient died as a result of an unrelated event. Patient-reported outcome measures and complications were collected through completion of patient and doctor questionnaires and clinical examination. Radiographic assessment of angular correction, joint congruity, and osteoarthritis was undertaken using standard radiology software. PAO survivorship was defined as nonconversion to THA and is presented using worst-case analysis. The loss-to-followup quotient-number of patients lost to followup divided by the number of a patients converted to THA-was calculated to determine quality of followup and reliability of survivorship data.
Results: The median preoperative Harris hip scores of 58 (range, 20-96) improved postoperatively to 78 (range, 33-100), 86 (range, 44-100), 87 (range, 55-97), and 80 (range, 41-97) at 1, 5, 10, and 14 years, respectively. Sink Grade III complications at 12 months included four relating to the PAO and one relating to the concomitant femoral procedure. The median lateral center-edge angle correction achieved was 22° (range, 3°-50°) and the median correction of acetabular index was 19° (range, 3°-37°). Osteoarthritis progressed from a preoperative mean Tönnis grade of 0.6 (median, 1; range, 0-2) to a postoperative mean of 0.9 (median, 1; range, 0-3). Six hips underwent conversion to THA: five for progression of osteoarthritis and one for impingement. At 12-year followup, survivorship of PAO was 94% (95% confidence interval [CI], 85%-98%) and survivorship with worst-case analysis was 90% (95% CI, 79%-96%). The loss-to-followup quotient for this study was low, calculated to be 0.3.
Conclusions: When PAO is performed using a structured process of mentoring under the guidance of an expert, one low-volume surgeon in a geographically isolated region achieved good patient-reported outcomes, a low incidence of complications at 12 months, satisfactory radiographic outcomes, and high survivorship. A structured distant-mentorship program may be a suitable method for initially learning and continuing to perform low-volume complex surgery in a geographically isolated region.
Level of evidence: Level IV, therapeutic study.